Trace amounts of radioactive material are brought to the surface during the production of hydrocarbons from subterranean formations. The radioactive material is typically suspended in formation waters produced from a reservoir and is carried to the surface with the waters. The radioactive material collects on metal surfaces and therefore tends to concentrate and accumulate on the inner surfaces of oil field tubulars and production equipment, such as storage tanks. The radioactive materials, which contaminate surface tubulars and equipment, are generally referred to as NORM. This NORM needs to be periodically removed from the oil field tubulars and production equipment. The removed NORM poses a potential environmental and health hazard and must be disposed of in an approved manner.
U.S. Pat. No. 5,202,522, to Williams discloses a method for disposing of radioactive material within a stable geological hydrocarbon-containing formation. The formation is penetrated by a steel tubular member and a concrete plug is set at the bottom of the tubular member. In the method, radioactive waste is mixed with concrete and pumped into the steel tubular member. Once the desired quantity of concrete has been added, the top of the steel tubular member is sealed off with clean concrete which does not contain radioactive material. The method is difficult to utilize because it requires mixing the radioactive material with concrete which then must be pumped into the steel tubular member to the region that will form the disposal area. The concrete slurry is difficult to work with and may spill during handling. Also, it must not be allowed to solidify before it reaches the disposal area. Additionally, the concrete slurry is viscous and heavy, and requires the use of complex handling and delivery equipment which usually must be decontaminated, further adding to the cost of disposing of the material.
What is desired is a method for disposing of NORM in a subterranean formation which provides for efficient handling and disposal of the NORM, while ensuring that the NORM is properly contained during storage, transportation, and handling.